The present invention relates to a method for treating bodies after crack splitting and a device for carrying out this method.
When crack splitting bodies, such as connecting rods, bearings, annular housings and the like, the material is subjected to what is called a forced rupture. This does not always result in a continuous, uniform crack even if the breaking notches are arranged in the crack splitting plane. It rather occurs that material particles are torn out from the crack surface during the splitting process, which initially adhere to the crack surface, but detach from the crack surface and fall out when a force acts upon the crack surfaces, as is the case, for example, when tightening the bolts of connecting rods or operating connecting rods later.
Such fall-outs occur in particular in the marginal areas of crack surfaces and can, in case the bodies concerned are bearings, even cause damage to these.
It is thus the object of the invention to provide a method and a device for preventing uncontrolled fall-out of loose or still partially adhering material particles.
This object is solved according to the invention by a method in which at least part of the crack-split body is subjected to a vibration treatment.
The invention is based on the idea of detaching adhering material particles from the crack surface by way of vibration treatment, and to subsequently convey these away from the crack surface area.
The vibration treatment can take place, dependent on the material of the connecting rod, within different frequency ranges. Tests have shown a frequency range of up to 20 Hz, in special cases up to 50 Hz, to be particularly suitable for vibration treatment.
The entire body can, as a matter of principle, be exposed to the vibration treatment. It is, however, expedient to hold part of the body during the vibration treatment, and to cause the remaining part to vibrate.
Various procedures are suitable for conveying away the detached material particles. Particularly good results are obtained by exposing the crack surfaces to air blast, especially in pulsating form.
The excitation for the vibration treatment can be generated in various manners, according to the requirements of each case. Thus, both pneumatic or hydraulic as well as electric or mechanical excitation are possible.
Good results are obtained if those parts of the body that are subject to the vibration treatment are clamped in and are mounted to slide within limits only in the excitation direction.
It is also advantageous if during vibration treatment, both parts of the body slightly contact each other in the area of the crack surfaces.
In principle, the vibration treatment can take place with or without the arrangement of additional elements, such as connecting rod bolts in the case of connecting rods. To the extent that the connecting rod bolts have already been screwed in a preceding operation, these bolts must be loosened by a few rotations prior to the vibration treatment, and tightened again after the vibration treatment.
It is another object of the invention to provide a device suitable for carrying out the said method.
According to the invention, such a device comprises a means for holding the bodies as well as a vibration means acting upon the bodies fixed on said holding means.
In this arrangement, the holding means can be designed in many. different ways. It is of advantage, however, to tightly clamp part of the body, i.e. the rod in the case of e.g. a connecting rod, in the holding means, and to move only the other part, i.e. the cap, relative to the rod by means of the vibration means.
To apply air blast, it is of advantage to provide a blowing means having nozzles. These nozzles can be configured in many different ways. It is, however, essential that they do not only convey the separated material particles away, but also contribute to their detachment from the crack surface.